The present invention relates generally to closure devices and, more particularly, to clamps for closing bags containing foods, potting soil compositions and other materials.
A survey of the prior art reveals that a need exists for a device for closing securely modern polymer bags. These bags afford significant protection to their contents and are generally economical in use. As a result, they are used for a variety of products ranging from foods such as potato chips, in relatively small and light bags, to potting soil compositions which are sold in larger and heavier bags.
The bags are generally of polymer construction with polyproplyene and polyethelene compositions being favored in some cases. These compositions tend to produce a bag that is impervious to environmental conditions such as pests and moisture. However, the bags often have slippery surfaces. This challenges inventors of bag closure devices since an effective bag closure device should effectively reclose a polymer bag, in spite of the slippery nature of the bag surface. Thus, a suitable closure device should protect bag contents by providing effective sealing of the bag.
In many cases, the bags are intended for repetitive use wherein the bag is opened, some contents are removed, and the bag is reclosed. Generally, it is important that the bag be securely closed. In the case of foods such as potato chips, for example, after the bag has been opened and some chips removed, it is desirable to have a technique for closing the bag to preserve freshness of the product and to prevent ants or other pests from gaining access to the chips. Thus, it is desirable to have an effective, easily used polymer bag closing device.
When heavier polymer bags, containing potting soil, for example, are utilized, a sturdy bag closing device is required. Desirably, the closure device would be of a type that does not become dislodged easily. Conventional clamping devices sometimes fail this test because they concentrate gripping forces near the clamp center. Movement of the heavy bag results in slippage of the bag at the clamp edges with spillage of bag contents sometimes resulting. This is due, in part, to the weight of the bag which, together with a slippery texture, can cause the bag to tear free of the clamping device.
Several conventional devices have been used to close polymer bags. Such devices are utilized, not only for closing food containers but also as clamping devices for garments and the like. In this regard, reference may be made to U.S. Pat. Nos. 4,394,791; 4,356,600; 4,660,750; 5,007,171; 5,305,500; 5,318,292; 5,457,858 and 5,802,677. In general, these devices have some utility but can be complicated and at least in some cases, they tend to slip, especially when heavy bags, such as potting soil bags are involved.
Accordingly, there is a need for an efficient, low cost and effective device for sealing a modern polymer bag. Such a device could be adapted for small bags and large while affording a substantial amount of purchase against the slippery surface of the bag.
From the foregoing it will be apparent that there is a need for a polymer bag closure device that is reliable, effective, mechanically simple, easy to use and low in cost. In addition to these characteristics, it would be highly desirable if such a device could have utility in opening polymer bags in an effective manner.
Polymer bags are notoriously difficult to open. This is due, in part, to the strength of the synthetic material and effective sealing of the bag during the manufacturing process. The result is a bag which can be very difficult to open. In some typical cases, the user forcefully attempts to separate bag surfaces. This action can cause a rupture of the bag seal, destruction of the bag and spillage of bag contents.
Conventional opening devices often sometimes fail when applied to polymer bags. Thus, it would be highly desirable to have an effective polymer bag clamping device having the above described characteristics and that would be useful for opening such a bag in a convenient manner.